Jochen Heinrichs from Göttingen started with this huge and nearly insoluble task, revising as a first step the neotropical Plagiochila species. Nearly 850 taxa are described from tropical America, that in his opinion may belong to 100-120 species. In the present work, a taxonomic revision of Plagiochila sect. Hylacoetes, sect. Adian- thoideae and sect. Fuscoluteae is presented, including a new classification of the group into nine monophyletic lineages. The study is based on molecular data (nrITS region), new morphological characters (e.g., capsul wall epidermis, oil bodies, surface waxes) and chemical investigations.

After an introduction and historical part, material & methods (phytochemistry, DNA extraction, PCR amplification, sequencing, selection of characters), the morphology and anatomy (stem structure and branching, leaves, underleaves, oil bodies, asexual reproduction, androecia, gynoecia, sporophyte, spores and elaters) are described. All taxonomic characters employed are treated in detail. Following is the phylogeny and sectional classification in nine lineages based on nrITS sequences of 38 species. These nine lineages are supported by high bootstrap percentage values, often assignable to morphological and phytochemical defined sections. Also problems were not ignored: e.g., the problems of intra-individual ITS polymorphism, as demonstrated for vascular plants, or interspecific hybridization and reticulate evolutionary phenomens are discussed, that makes a general applicability of the ITS region for phylogenetic analysis problematical. The first part of the study is finished by an overview and description of these nine sections, including the differentiating characters in tabular form.

The main part of the book is the taxonomic treatment of the three independant lineages assignable to sect. Hylacoetes, sect. Adianthoideae, and sect. Fuscoluteae. The main diagnostic characters of these are:

P. sect. Hylacoetes: characterized by the absence of surface wax, a capsule wall epidermis without thickenings on the cell walls and usually fan-shaped terminal androecia with bracts not overlaping dorsally. This section comprises 18 species, among them the former monospecific genera Szweykowskia and Steereochila, that clearly nested in the molecular analysis within the P. sect. Hylacoetes clade.

P. sect. Adianthoideae: characterized by the absence of surface wax, a capsule wall epidermis with thickenings on the cell walls and simple, intercalary androecia with bracts overlaping dorsally. Here, four species are included.

P. sect. Fuscoluteae: characterized by the presence of surface wax, a capsule wall epidermis with thickenings on the cell walls and simple, intercalary androecia with bracts not overlaping dorsally. This section comprises nine species.

Within each section a dichotomous key is given and each species is fully described. As might be expected, many species have an extensive synonymy. The detailed specific descriptions of the gametophyte and sporophyte are accompanyied by line drawings of all, but one species (P. rudischusteri; 46 plates), citation of representative specimens examined, distributional and ecological notes. The descriptions and illustrations are very good and serves its purpose well. Highly welcome are the remarks on differentiation and variation of the species. Beside one new species, P. patriciae from Costa Rica, the study includes three new combinations [comb. & stat. nov.: P. dimorpha var. ecuadorica (= Steereochila ecuadorica), P. superba var. macrotricha (= P. macrotricha), and P. heterophylla var. beauverdii (= P. beauverdii)] and about 77 taxa are brought to synonymy. 12 plates based on SEM studies of surface wax structures, spores and elaters add to the excellent overall impression. Up to now, 60 Neotropical Plagiochila species can be differentiated, which represent about half of the expected number of species. The present treatment includes 31.

As a further main result of the study, P. sect. Subplanae now is treated as a synonym of the former palaeotropical section Cucullatae, due to the similarities in morphology (capsule wall structure) and the molecular analysis. This leads to a range extension of this section to the Neotropics. Its single representant in the Neotropics is P. subplana.

Revising a notoriously difficult genus such as Plagiochila is certainly no piece of cake. It seems to me, that Heinrich has done a very good work and progressing well in revising neotropical Plagiochilas. With this excellent, thoroughness and com- prehensiness account on the neotropical species, Heinrichs therefore fills a huge gap. But the work has also shown, that natural groups (monophyletic lineages) of neotropical Plagiochilas often have no autapomorphisms. Therefore they can be identified only on the basis of tendencies of characters. Absolute diagnostic characters are infrequent. The quality of a revision must be measured by the working ability of the identification keys. I was not able to test the keys completely, but I have the feeling, that the identification of neotropical Plagiochilas will be not easy, also in future. Nevertheless, this revision is urgently needed and is a must for bryologists, especially those working in the Neotropics.

HARALD KÜRSCHNER, Berlin

Nova Hedwigia vol. 76, no. 1-, pp. 269-271

Les espèces de la sect. Superbae Carl. illeg. sont réparties dans les sections Hylacoetes et Adiantoideae. Les membres de la sect. Hylacoetes sont caractérisés par un épiderme pariétal de la capsule sans épaississement des parois, et avec des androécies terminales, habituellement en éventail ; ceux de la sect. Andiantoideae ont un épiderme pariétal de la capsule avec des épaississements des parois cellulaires noduleux et des androécies simples et intercalées ; ceux de la sect. Fuscoluteae ont une cire de surface. Des clés aux membres des trois sections sont données.

Chaque taxon est décrit (gamétophyte et sporophyte) et illustré, accompagné de données de distribution et d'écologie.

La sect. Adiantoideae comprend 4 espèces restreintes aux Néotropiques. La sect. Hylacoetes comporte seize espèces (dont P. patriciae sp. nov. ) qui ne sont pas restreintes aux seuls Néotropiques. La sect. Fuscoluteae (P. Sect. Bursatae Carl, syn. nov. ) inclut 8 espèces res- treintes aux Néotropiques à l'exception de P. heterophylla Lindenb. ex Lehm. présente en Europe atlantique sous le nom de P. atlantica F. Rose. Les excellents dessins au trait des différentes espèces, les très bonnes photographies au microscope électronique à balayage du sporoderme, des spores et des élatères forment une très utile illustration à ce travail minutieux de synthèse d'un genre d'hépatique très complexe.

En appendices : les spécimens étudiés pour telle ou telle technique, les caractères utilisés pour le traitement cladistique. Bibliographie, pp. 166-178 ; index des noms, pp. 179-184.

Cryptogamie, Bryologie 2002, 24 (1)